When reassembling the fan make sure the notches in the center of the fan blade line up with the protrusions in the motor's shaft.
Page 4 of 9
GD Midea FT30-3D Motor Replacement
Step 5 — Oscillation Mechanism
Remove the rear fan guard by taking off the plastic nut that holds the rear fan guard to the upper assembly.
The plastic nut needs to be twisted off; like a screw.
Step 6
Remove the screw at the center of the oscillator knob and remove the oscillator knob.
If the oscillator knob is clean and undamaged then the problem is with the oscillator. If the knob is damaged replace it and test your fan before proceeding forward in the guide.